Process for obtaining transparent effects on regenerated cellulose fibers



Patented May 2, .1950

PROCESS FOR OBTAINING TRANSPARENT EFFECTS ON REGENERATED CELLULOSEFIBERS Paul Walter Steinlin, Basel, Switzerland, assignor toAktiengesellschaft Cilander, Herisau, Switzerland No Drawing.Application July 31, 1946, Serial No. 687,511. In Switzerland April 22,1943 6 Claims. (01. 8-118) The present application is in the nature of acontinuation in part of my earlier copending application Serial No.533,788, filed May 2, 1944, now abandoned.

Transparent fabrics, also known as organdies, have as a rule been madefrom pure cotton materials, in particular muslin, or, more rarely voileor other fine fabrics, such as cambric, etc. Organdies of especiallyfine quality were made of natural silk.

The process hereafter described relates to the production of plain orpatterned, smooth or crepe transparent fabrics from materials consistingof staple fibre made from regenerated cellulose alone or of staple fibremade from regenerated cellulose and cotton, or of mixed cotton andstaple fibre made from regenerated cellulose.

Various experiments were made in the past to transform textiles of thiskind by th ordinary methods used for cotton fabrics. However, even byvarying and adapting working conditions, such as concentration of acidsand alkaline swelling agents, and the duration of the procedure, itproved impossible to turn out marketable goods. Indeed the materialshitherto produced were horny, brittle and stiffened, and in no waysuited for practical use. The present process, on the contrary, producestransparentfabrics which perfectly satisfy all. requirements as toappearance, lustre, softness and durability, and show a high degree oftransparency combined with a remarkable clearness of weave.

These effects are obtained by subjecting the fabric, eventually afterpreparatory or supplementary treatment with alkaline or acid swellingagents, first to a treatment as usual with strong, hot alkali, thenrinsing and neutralizing, and again subjectin it to the action ofstrong, hot alkali.

The process is suited for fabrics made of pure staple fibre made fromregenerated cellulose, or woven with cotton and staple fibre, and alsofor those woven with mixed staple fiber made from regenerated celluloseand cotton yarn. Naturally, materials in which any or all of the abovecombinations are present, either in plain or pattern weave, including ofcourse applications with embroidery or Swiss dotted weave, can also betreated by my process.

It is advantageous to delubricate and bleach the fabric to be processed.Crude fabrics can, however, be treated in the same way. In thisconnection it should be borne in mind that, according to the invention,this processing is suitable ior use in any phase of pre-treatment.

My process can be used to advantage in combination with treatment byswelling agents. The manner and order in which these treatments areapplied depend on the result desired.

By hot alkali is understood a treatment according to the present processwith hot alkali solution of mercerizing strength, at a temperature of C.or over, having a duration of 5 seconds or more.

It is not necessary to rinse and neutralize the fabric between the twoconsecutive alkaline treatments. Nevertheless, the effect is heightenedby so doing. Repeating the process several times also tends in the samedirection.

Patterned as well as plain transparent fabrics can be obtained with thepresent process by applying suitable reserves before the swellingtreatment. For example in opaque non-transparent patterns. By thismethod it is possible, according to the type of process chosen, to usepigment carriers proof against acid and alkaline swelling agents, suchas gums or artificial resins, which result in local opaque effects, ornon-acidproof thickening agents which produce stiffened transparentdesigns in which the effect of contrast is due to the pigmentationalone. It is moreover possible to introduce reserves during any phase ofthe transforming process so as to achieve, for example, a transparenteffect and then, by rinsing and subsequent swellin and shrinking, obtainthe appearance of crepe. It is also possible to get intermediary effectsby the imprint of swelling agents and subsequent treatment with hotalkali. The reserves can even be applied during various phases of theprocess in such a way that the transformed material shows untreated. andswollen, that is shrunken and transparent areas one next to the other.

It is evident that by printing in colours or by the use of colouredreserves such effects can be obtained in various tints.

Fabrics submitted to the present process can be dyed either before orafter treatment. In this way, according to the method of procedure, themost varied results can be obtained, such as plain transparent, or,according to the different affinity for the dye caused by difierentlocal treatment, shaded effects.

My process may be illustrated by means of a single example:

A singed, bleached and tentered fabric made from staple fibre made fromregenerated cellulose is treated with NaOH of 30 B. at C. for

imago effects can be achieved by printing with pigments, resulting 8seconds, rinsed and neutralized, and finished with NaOH of 31 B. at 450.

Another embodiment of the process consists in preparing a fabric madefrom staple fibre made from regenerated cellulose as above, subjectingit to the first alkaline treatment, neutralizing, rinsing and drying it,and then applying the second alkaline treatment.

In both cases the result is a soft, lustrous fabric with lighttransparency and elastic feel.

I claim:

1. A multiple-step process for obtaining transparent effects on a fabricconsisting predominantly of regenerated cellulose staple fiberscomprising treating said fabric with a hot caustic soda of mercerizingstrength at temperatures of the order of 55 C. for a period of time ofthe order of 5 to 8 seconds, removing free caustic soda from the fabric,and then treating said fabric with a hot caustic soda of mercerizingstrength at temperatures of the order of 45 C. for at least 5 secondsbut not substantially more than 5 seconds.

2. A multiple-step process for obtaining transparent effects on a fabricconsisting predominantly of regenerated cellulose staple fiberscomprising treating said fabric with caustic soda of the order of 30Baum at a temperature of the order of 55 C. for a period of time of theorder of 5 to 8 seconds, and then treatingsaid fabric with causticsodaof the order of 31 Baum at a temperature of the order of 45 C. for aperiod of time of the order of at least 5 seconds but not substantiallymore than 5 seconds.

3. A multiple-step process for obtaining transparent effects on a fabricconsisting predominantly of regenerated cellulose staple fiberscomprising treating said fabric with caustic soda of the. order of 30Baum at a temperature of the order of 55 C. for a period of time of theorder of 5 to 8 seconds, removing free caustic soda from the fabric, andthen treating said fabric with caustic soda of the order of 31 Baum at atemperature of the order of 45 C. for a period of time of the order ofat least 5 seconds but not substantially more, than 5 seconds.

4. A multiple-step process for obtaining transparent efiects on a fabricconsisting predominantly of regenerated cellulose staple fiberscomprising treating said fabric with caustic soda of the order of 30Baum at a temperature of the order of C. for a period of time of theorder of 5 to 8 seconds, rinsing and drying said fabric, and thentreating said fabric with caustic soda of the order of 31 Baum at atemperature of the order of 45 C. for a period of time of the order ofat least 5 seconds but not substantially more than 5 seconds.

5. A multiple-step process for obtaining transparent effects on a fabricconsisting predominantly of regenerated cellulose staple fiberscomprising treating said fabric with caustic soda of the order of 30Baum at a temperature of the order of 55 C. for a period of time of theorder of 5 to 8 seconds, rinsing, neutralizing, and drying said fabric,and then treating said fabric with caustic soda of the order of 31 Baumat a temperature of the order of 45 C. for a period of time of the orderof at least 5 seconds but not substantially more than 5 seconds.

6. A multiple-step process for obtaining transparent effects on a fabricconsisting predominantly of regenerated cellulose staple fiberscomprising treating said fabric with caustic soda of the order of 30Baum at a temperature of the order of 55 C. for a period of time of theorder of 8 seconds, rinsing, and neutralizing the fabric, and thentreating said fabric with caustic soda of the order of 31 Baum at atemperature of the order of 45 C. for a period of time of the order ofat least 5 seconds but not substantially more than 5 seconds.

PAUL WALTER STEINLIN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Italy Mar. 11, 1936

1. A MULTIPLE-STEP PROCESS FOR OBTAINING TRANSPARENT EFFECTS ON A FABRICCONSISTING PREDOMINANTLY OF REGERATED CELLULOSE STAPLE FIBERS COMPRISINGTREATING SAID FABRIC WITH A HOT CAUSTIC SODA OF MERCERIZING STRENGTH ATTEMPERATURES OF THE ORDER OF 55*C. FOR A PERIOD OF TIME OF THE ORDER OF5 TO 8 SECONDS, REMOVING FREE CAUSTIC SODA FROM THE FABRIC, AND THENTREATING SAID FABRIC WITH A HOT CAUSTIC SODA OF MERCERIZING STRENGTH ATTEMPERATURES OF THE ORDER OF 45*C. FOR AT LEAST 5 SECONDS BUT NOTSUBSTANTIALLY MORE THAN 5 SECONDS.